1. Field of the Invention
The present invention relates to an endoscopic surgical procedure on a patient, and more particularly, is directed to a novel and unique endoscopic surgical procedure known as an endoscopic gastrocnemius tenotomy. In particular the surgical procedure may be implemented by means of a unique endoscopic surgical instrument in the form of a slotted cannula incorporating a novel locking device for an endoscopic instrument and for the surgical cutting element, such as a knife blade or rasp; and selectively, a depth gauge including calibrating structure for measuring the length or depth of the intended surgical procedure. Also incorporated therein is a calibrating structure for the endoscopic knife; and a stop device for use with the endoscopic knife and/or the depth gauge, and which is adapted to be employed in the implementation of the foregoing method of endoscopically effecting the above-referenced surgical procedure; this instruments being disclosed in Mirza U.S. Pat. No. 5,968,061; the disclosure of which is incorporated herein, and discussed hereinbelow in connection with the inventive endoscopic surgical procedure.
In particular, although initially described herein as being directed to the above-mentioned aspect of implementing a specific endoscopic surgical procedure, numerous other surgical procedures may be readily implemented employing the Mirza endoscopic surgical instrument, as mentioned hereinbelow.
Basically, improved endoscopic surgical procedures and endoscopic instruments are disclosed and directed to the implementation of endoscopic carpal tunnel release and other diverse surgical applications; as set forth in Mirza U.S. Pat. No. 5,366,465, issued Nov. 22, 1994, and U.S. Pat. No. 5,578,051, issued Nov. 26, 1996, and U.S. Pat. No. 5,968,061 issued Oct. 19, 1999 the disclosures of which are incorporated herein by reference.
Among more recent developments and advances in such surgical procedures, arthroscopic surgery employing the use of endoscopic devices has found widespread application, in that in comparison with earlier customary surgical methods, any incisions necessary for such endoscopic/arthroscopic surgical procedures have been considerably reduced in size, thereby alleviating potential postoperative complications and pain encountered by the patient, while reducing any scarring to cosmetically desirable levels. Among various types of surgical procedures, techniques involving approaches by means of arthroscopic and endoscopic systems to carpal tunnel surgery have been acknowledged as being superior in providing significant advances over earlier so-called open surgical procedures necessitating large incisions. Such endoscopic surgical procedures have found widespread acceptance in effectuating carpal tunnel release for the purpose of alleviating the symptoms in a patient caused by carpal tunnel syndrome, also referred to as tardy median nerve palsy, normally caused by the compression of the median nerve within the carpal tunnel.
More recently, consideration has been given towards extending the scope of the endoscopic surgical procedure to other aspects such as plantar fascia release associated with heel spur syndrome in which a patient encounters severe pain at the bottom of the foot. This aspect, which is caused by the dense fibrous band of tissue which is known as the plantar fascia, is that a disorder of the foot, such as a structural misalignment, can cause an inflammation and result in intense pain in the foot. Although in many instances therapy may remedy the problems which are encountered, at times surgery is necessary in order to alleviate the problems.
Among these problems, posterior heel cord contracture (ankle equines) has been implicated in many types of foot and ankle deformities. Lengthening of the Achilles tendon and the associated gastrocnemius-soleus complex has been advocated in reducing these equines deformities. This can be done as an open or a percutaneous procedure. The open procedures tend to have unappealing cosmesis and greater risk of wound complications. Percutaneous procedures do not allow for direct visualization. Furthermore, the functionality of posterior lengthening procedures has not been fully assessed. Over-lengthening can be disastrous, especially for patients who need to be able to stand on their toes. For purposes of illustration, the invention is described with regard to the implementation of an endoscopic surgical procedure employed in the treatment of posterior heel cord contracture.
2. Discussion of the Prior Art
Among numerous publications which describe recent advances in endoscopic surgical methods and instruments employed in connection therewith, there may be found the Agee carpal tunnel release system as disclosed in Agee, et al. U.S. Pat. Nos. 4,963,147 and 5,089,000, both of which disclose endoscopic surgical instruments and surgical procedures implemented therewith, which when applied to carpal tunnel release through an effective severing of the flexor retinaculum, or transverse carpal ligament, are adapted to provide relief to the patient.
Another surgical system and instrument providing for an advanced technique over Agee, et al., which is particularly adapted for carpal tunnel release through the intermediary of an endoscopic surgical procedure is disclosed in Chow U.S. Pat. No. 5,029,573. However, in that instance, although setting forth a considerable advance over the methodology disclosed in the Agee, et al. U.S. patents, the surgical procedure employed by Chow requires the formation of two entry and exit portals or incisions, one in the wrist area and one in the palm, and the passage of an endoscopic medical instrument, such as an obturator through a considerable length beneath the subcutaneous areas of the palm of the patient.
Another method of endoscopic surgery and instrument for implementing surgery, particularly for the release of the carpal tunnel, are disclosed in Brown U.S. Pat. No. 5,323,765. Although Brown directs the endoscopic surgery towards alleviating the syndrome encountered with the carpal tunnel, as in the previously discussed publications, two separate incisions are required. Moreover, although Brown also briefly mentions the application of the surgery and instrument or apparatus to the treatment of the foot, particularly the plantar fascia, again there is no detailed explanation provided as to the method in which this is accomplished, and apparently this would also necessitate providing a plurality of separate incisions to implement the surgery.
More recently, as described in Mirza U.S. Pat. No. 5,366,465, the foregoing limitations and potential drawbacks which are encountered in the previously mentioned prior art publications have been improved upon through a novel method of implementing endoscopic surgical procedures, and a unique and inventive endoscopic surgical instrument developed for accomplishing this purpose, which has proven itself to be especially suited for, but not limited to, the effectuation of carpal tunnel release. In essence, the Mirza patent is directed to the severing of the flexor retinaculum or transverse carpal ligament through an endoscopic surgical procedure in which there is effected, by means of a uniportal or single incision, a palmar subligmentous endoscopic carpal tunnel release technique. This surgical procedure only requires the formation of a single and relatively small entry portal or incision in the palm proximate the distal side of the flexor retinaculum, thereby reducing any postoperative symptoms of the patient with only a cosmetically appealing scar formed on the palm, while eliminating the need for a second portal or incision proximate the wrist of the patient; and concurrently avoiding injury to the palmar arch and branches of the median nerve. Moreover, the endoscopic instrument employed in implementing the surgical method utilizes a cutting device which is mounted on a scope insertable through a cannula which has been initially inserted to extend beneath the flexor retinaculum from the distal side of the flexor retinaculum or transverse carpal ligament, upon the formation of a passage beneath the flexor retinaculum, after hyperextending of the hand, by the preceding insertion and manipulation of a curved dissector. Thereafter, the dissector is removed and the cannula and an obturator which is contained therein are inserted through the incision into the previously formed passage beneath the flexor retinaculum. The cannula of the surgical instrument has the obturator withdrawn therefrom, and in place of the latter, a scope is inserted into the cannula which enables unhindered and unobstructed visualization of the operating site and of the flexor retinaculum.
The scope is then withdrawn from the cannula, and the same scope or another scope with a cutting blade mounted at the leading end thereof inserted into and advanced through the cannula towards the flexor retinaculum. Severing of the latter is then effected by the cutting blade while affording an unhindered view of the operating site through the scope, thereby resultingly dramatically reducing or even completely eliminating the risk of any injury being sustained by tissue and nerves in the vicinity of the operating site; for example, such as the median nerve. This particular unhindered visualization of the operating site also enables the surgeon to exercise an improved degree of control over the possibly single-handed manipulation of the endoscopic instrument and cutting blade.
The cannula of the endoscopic instrument, which contains the obturator which is initially employed to be advanced beneath the flexor retinaculum or transverse carpal ligament subsequent to withdrawal of the curved dissector, may be provided with lateral or sideways wing-like or flange-like protrusions of curvilinear configurations which, in conjunction with an upwardly curving tip of the obturator projecting forwardly of the leading end of the cannula, is adapted to displace any tissue, or such as the media nerve, out of the path of the obturator and cannula as is being advanced; in effect, through essentially a sideways or lateral “shoving” action, thereby preventing any potential damage to such displaced tissue and nerve during the subsequent cutting procedure by maintaining such tissue well out of the way. Moreover, the leading tip of the obturator by being curved slightly upwardly towards the lower surface of the flexor retinaculum is also adapted to remove or dislocate any possible tissue or fascia located close to the surface of the flexor retinaculum and to ensure that the cannula and, resultingly, the subsequently inserted cutting blade are located as closely as possible to the flexor retinaculum.
Although described hereinabove with regard to the effectuation of a carpal tunnel release, the inventive uniportal endoscopic surgical methods and instrument may be also be readily applied to other surgical procedures; for example, such as uniportal plantar fascia release, lateral release for patella realignment, release of the posterior and other compartments of the leg, and forearm fascia release for fascial compartment syndrome. To that effect, reference may be had to the disclosure of Mirza U.S. Pat. No. 5,578,051 which considerably expands the surgical field of applications of the previous Mirza patent and also incorporates additional features in the endoscopic surgical instrument.
The foregoing endoseopic surgical methods, particularly the uniportal surgical procedures and surgical instruments developed by the Mirza U.S. Pat. Nos. 5,366,465, 5,578,051 and 5,968,061, the disclosures of which are incorporated herein by reference, although providing considerable advantages over the current state of the art, are still further simplified by providing an improved composite slotted cannula and dissector of unitary or integral construction which eliminates a need for the provision of a separate dissector or a separate obturator, thereby reducing the number of surgical steps in the implementation of the various procedures. A particular aspect of eliminating the separate dissector and obturator heretofore utilized resides also in the composite cannula and dissector which forms the passageway towards the surgical site enabling an improved control during insertion thereof, and by reducing the surgical steps during the implementation of the procedure renders the entire operation less expensive and of shorter duration, so as to further minimize any potential discomfort to a patient.